Heavy duty apparatus such as vibratory conveyor belts, chain hoists, and the like that have an intermittent load are often driven by power bands or drive belts from an electric motor. Tension on the band is maintained by supporting the motor on a pivoting motor mount. A platform holds the motor. An elongate sleeve affixed to the underside of the platform pivots on a stationary axle that is mounted on a fixed base. A non-cylindrical resilient member between the sleeve and the axle provides spring bias. In another type of mount, spring bias is provided by a compression spring between a pivoting axle and the base. The band slips when excessive load is applied, such as at start up. This causes excessive band wear, leading to band failure. In many cases, the operating cost of band failure is many times greater than the cost of a new band, since maintenance personnel may not be at hand. The entire operation may be stopped for days.